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The Getty Conservation Institute Newsletter

Volume 15, Number 3 2000

Front cover: Detail of James Ensor’s paintingChrist’s Entry into Brussels (1889) beingcleaned in 1988 with the gels cleaningprocess. The GCI is currently conducting aresearch project to answer questionsregarding the long-term effect of cleaningwith the gels systems. Photo: Mark Leonard.

The J. Paul Getty Trust

Barry Munitz President and Chief Executive Officer

Stephen D. Rountree Executive Vice President and Chief Operating Officer

John F. Cooke Executive Vice President, External Affairs

Russell S. Gould Executive Vice President, Finance and Investments

The Getty Conservation Institute

Timothy P. Whalen Director

Jeanne Marie Teutonico Associate Director, Field Projects and Conservation Science

Kathleen Gaines Assistant Director, Administration

François LeBlanc Head of Field Projects

Alberto de Tagle Chief Scientist

Marta de la Torre Head of Information & Communications

Conservation, The Getty Conservation Institute Newsletter

Jeffrey Levin Editor

Joe Molloy Graphic Designer

Color West Lithography Inc. Lithography

The Getty Conservation Institute works internationally to advance

conservation practice in the visual arts—broadly interpreted to

include objects, collections, architecture, and sites. The Institute

serves the conservation community through scientific research into

the nature, decay, and treatment of materials; education and train-

ing; model field projects; and the dissemination of information

through traditional publications and electronic means. In all its

endeavors, the GCI is committed to addressing unanswered ques-

tions and promoting the highest possible standards of conservation.

The Institute is a program of the J. Paul Getty Trust, an international

cultural and philanthropic institution devoted to the visual arts and

the humanities that includes an art museum as well as programs

for education, scholarship, and conservation.

Conservation, The Getty Conservation Institute Newsletter,

is distributed free of charge three times per year, to professionals

in conservation and related fields and to members of the public

concerned about conservation. Back issues of the newsletter,

as well as additional information regarding the activities of the GCI,

can be found in the Conservation section of the Getty’s Web site.

http://www.getty.edu/gci

The Getty Conservation Institute

1200 Getty Center Drive, Suite 700

Los Angeles, CA 90049–1684

Telephone: 310 440–7325

Fax: 310 440–7702

onte

ntsFeature 5 Surface Cleaning and Conservation

The cleaning of works of art and historic monuments—as an evolving idea and in practice—

has had a long history. Since ancient times, the condition of cleanliness has been under-

stood as a symbol of purity and integrity. In later periods, when decay and patina were

appreciated as testimony of genuine origin and true age, cleaning was less favored by many.

Today, with cooperation between conservators, art historians, and scientists, a balanced

understanding of the problems of cleaning seems to have been reached, one that relies on

a common agreement of the historical uniqueness of every artistic or cultural relic.

20 Preservation in St. Petersburg As St. Petersburg prepares for its th birthday in , the St. Petersburg International

Center for Preservation is assuming a vital role as the only noncommercial organization

devoted exclusively to cultural heritage preservation in this World Heritage City. The

mission of the Center—an independent organization backed by a coalition of institutions

in St. Petersburg, the United States, and Europe—is to encourage and facilitate modern

conservation strategies through professional programs in education and training, informa-

tion services, collaborative scientific research, and heritage advocacy.

GCI News 23 Projects, Events, Publications, and StaffUpdates on Getty Conservation Institute projects, events, publications, and staff.

News in 16 The Gels Cleaning Research Project Conservation In the early s, Richard Wolbers of the University of Delaware introduced gels cleaning

systems to the conservation community. Because of important advantages, these cleaning

systems are now widely used in conservation lab practice. The —in collaboration with

colleagues at the Winterthur Museum, Gardens, and Library, the Winterthur–University

of Delaware Program in Art Conservation, the Chemistry Department of California State

University, Northridge, and the Getty Museum—has been carrying out in-depth research

on the gels cleaning systems and their long-term effects on painted surfaces.

Dialogue 10 Finding a Certain Balance A Discussion about Surface CleaningThree conservators that head up Getty Museum conservation departments—Brian

Considine of decorative arts and sculpture, Mark Leonard of paintings, and Jerry Podany

of antiquities—discuss some of the philosophical and technical issues related to the surface

cleaning of objects in museum collections.

C

A Note fromthe DirecorBy Timothy P. Whalen

I the Institute’s

work in these pages, and I want to take this opportunity to update

you on our progress.

There are several significant staff changes that I’m delighted

to announce. Jeanne Marie Teutonico has been named associate

director for Field Projects and Conservation Science. This

appointment should help us integrate the work of these two

groups in a way that strengthens our contributions to the field.

I am also pleased that François LeBlanc—chief architect at the

National Capital Commission in Ottawa, Canada—will join us

as head of Field Projects. We are honored to have him lead this

important program.

Since I arrived at the two years ago, we have assessed our

strengths, focused our work to complement that of the Getty Trust,

and consolidated our activities in our traditional areas of expertise.

Ultimately, our raison d’être is to serve the field of conservation by

providing tools and resources for those responsible for the care and

conservation of art, architecture, and archaeology. To do that, we

are organized into four groups: Conservation Science, Field Pro-

jects, Education, and Information and Communications. Each

group includes highly dedicated staff who work with a wide array of

institutional partners and colleagues—and with our conservation

colleagues in the other Getty programs.

We will soon name a head for the Education Group, which is

quickly taking shape. I’m pleased with the response to the ’s

new visiting scholars program, which offers an opportunity for

conservation professionals to examine important questions, freed

from the grind of practice, lab, and field. The Education Group

will contribute essential resources to individuals and institutions

that teach conservation, in part by publishing important readings

in conservation as well as translations of significant works. We will

continue to work closely with the conservation training programs

to examine ways that the teaching of conservation professionals

can be advanced.

During this last year, we had some notable accomplishments,

including the Second Pan-American Course on the Conservation

and Management of Earthen Architectural and Archaeological

Heritage, held in Peru. This summer saw the completion of the

4 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lDirector’s Note

conservation of The Last Judgment, the th-century glass mosaic

that is one of the Czech Republic’s most significant cultural trea-

sures. During this year, the —in collaboration with colleagues

inside and outside the Getty—continued conducting scientific

research that has made strides in addressing questions regarding

gels cleaning systems. Several projects involving the conservation

and management of sites are ongoing in Central America, the

Mediterranean, and China.

In the year ahead, we have a meeting planned in Spain on

retablo conservation and a workshop scheduled for Brazil on build-

ing-related aspects of environmental management. We will begin

research with our partners at the Image Permanence Institute—

and at the Centre de recherche sur la conservation des documents

graphiques in Paris—on the conservation of photographic collec-

tions. And we’ll explore research needs related to the conservation

of modern and contemporary art, in collaboration with a number

of major art museums.

Art and Archaeology Technical Abstracts (AATA) is being

strengthened, and within months we will launch it as a Web-

based resource, in partnership with our colleagues at the . As we

expand its coverage and make it more accessible and comprehen-

sive, we are grateful for the tireless efforts of AATA’s technical

editors and volunteer abstractors, without whom the publication

would not exist.

Locally, we are working with the City of Los Angeles on the

conservation and presentation of the David Alfaro Siqueiros mural

América Tropical. We have a generous partner in our local support

group, Friends of Heritage Preservation, and we anticipate—

pending city approvals—that the mural will be accessible to the

public in .

I hope you’ll visit the Getty’s newly launched Web site:

http://www.getty.edu . It incorporates all the Getty Trust’s

activities, including descriptions of the ’s work and a range of

conservation resources. Please let us know what you think of the

conservation components of the site by writing us at:

gciweb@getty.edu .

Because the needs of the conservation field are vast, no single

organization can provide all the resources and solutions necessary

to address them. I expect, however, that anything the Institute pur-

sues will broadly serve the conservation community, in part because

we work with conservation organizations and professionals around

the world who offer skill and expertise that complements our own.

I’m grateful to our partners—and to the staff of the —for the

commitment and talent they bring to advancing conservation

worldwide. Please accept my best wishes for the holidays and for

peace in the new year for you and your family.

By Manfred Koller

Surface Cleaningand Conservation

Feat

ure

The 1754 portrait of Jan van Dijk,painted by Jan ten Compe. Between1746 and 1766, the City of Amsterdammade numerous payments to van Dijkfor the cleaning and restoration ofpaintings owned by the municipality.Photo: Courtesy the AmsterdamsHistorisch Museum.

TT and historic monuments

generally results in substantial physical changes to the surface of

the objects. From the subjective standpoint of the viewer, there are

visual changes as well. Because visual sensations and reactions

depend on the viewer’s consciousness, experience, and knowledge

of art and history, discussions regarding cleaning have to respect

differences in cultural background and visual education.

While cleaning can be a technical necessity for proper

conservation, it usually is done for aesthetic or other reasons.

Cleaning as a technical necessity has been nearly overlooked in the

past; cleaning for aesthetic reasons has been under discussion since

early times. In many instances, as a consequence of cleaning, other

issues—such as how to present the areas of loss or whether or not to

apply new protective and unifying coatings on the surface—have to

be solved. In the following review of cleaning and conservation, my

focus is primarily on painting (representing an indoor environment)

and on monuments (representing an outdoor one).

The Evolving Idea of Cleaning

The literal significance of clean is free of dirt, stains, or anything

that dulls luster or transparency. But since ancient times the

condition of cleanliness has also been understood as a symbol of

purity and integrity. Cleaning served as a purgative for religious

purposes—for example, as a component of the rules for the

dressing and the food of priests or the immaculate presentation of

venerated statues. Even in profane life, the idea of cleanliness was

important. The buildings and places of Greek and Roman towns

followed certain guidelines for public order. In medieval central

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lFeature 5

St. Peter’s Basilica in the Vatican after being cleaned in honor of the Jubilee Year 2000. In the 17th and 18th centuries, Roman churches were washed every 25 years in honor of “holy years.” Photo: Marta de la Torre.

Italy, new communities set up rules to maintain the visual harmony

of their buildings in order to assure positive public representation

of townships. This concept continued until the th century with

public control of civic buildings. Often cleaning has been connected

with the celebration of anniversaries, done to show physical and

visual rebirth—in Latin called renovatio or restitutio. Between

and , churches in Rome were whitewashed every years to

celebrate “holy years.”

With the development of science and of philosophical

concepts of rationalism in the Age of Enlightenment, a basic refor-

mation in economics, society, and the arts occurred. When Isaac

Newton identified the spectral composition of light around ,

the nature of pure color became evident for the first time. It cannot

be accidental that shortly thereafter, following debates in the acad-

emy of arts in Paris, the priority of color was officially emphasized.

Similarly, in Venice, the dark tonality of paintings (from the so-

called tenebrosi painters) changed to a bright and clear palette.

The theory and the practice of art have always influenced those of

restoration, as has the general development of society and mind.

(For example, after the American wars for independence and the

French Revolution, the ideals of liberation and freedom became

dominant; in the following period of romanticism, cleaning was

given even a moral value as liberation from all earlier alterations—

a recovery of the “original” nature of material and the believed

authentic creation of the artist.)

The first definitions of cleaning and patina related to works

of art were noted by Tuscan artist Filippo Baldinucci in the latter

part of the th century. In his Italian vocabulary, to clean (pulire)

means not only to take away dirt and stains but also to polish—

mainly marble and metal. He called patina (patena) “some univer-

sal darkness which time made to appear on pictures and that

sometimes favors them.” This remark reflects the view already held

by the antiquarians and connoisseurs of the time. But patina and

other darkness were appreciated in other respects. It was forbidden

to clean certain venerated religious statues or paintings such

as icons, and only tinted varnishes were periodically applied;

over time, these became nearly black, a condition that was desirable

for its mystic appearance (an example is The Black Madonna of

Czestochowa, Poland).

Another antiquarian idea against cleaning during the th

century was the appreciation of decay and patina as testimony of

genuine origin and true age. Pieces in this kind of condition

brought a good price in the art trade. William Hogarth offered a

critique of this esteem for age in his famous and ingenious

engraving Time Smoking a Picture. The inscription below the

engraving connects it to the paradox of a contemporary intellectual

controversy: “As Statues moulder into Worth.” From the late

th century and into the th century, the application of colored

6 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lFeature

varnishes and dark surfaces became fashionable as a way to evoke

sentimental feelings of mystery and ideal harmony. This corre-

sponded to the contemporary philosophy of aesthetic idealism.

Technical problems in cleaning pictures were discussed in

many painters’ books before and after , following the growing

professional specialization of “restorer.” This specialization was

guided by leading members of the art academies. They oversaw

the practice of restoration of public patrimony and also prevented

radical cleaning of outdoor sculptures—for example, the Trinity

Column monument in Vienna in . New understandings of

architectural surfaces were revealed in the debates about poly-

chromy in antiquity. The protagonists—architects Leo von Klenze

and Gottfried Semper in Germany and Jacques Ignace Hittorff in

France—approved of the presence of color, as opposed to the neo-

classic ideal of the pure material devoid of color.

In the middle of the th century, with mainly medieval

architecture in mind, John Ruskin was the first to condemn all

attempts at uncovering and radical cleaning as destruction of what

should have been preserved. “The whole finish of the work was in

the half inch that is gone,” he wrote. “Take proper care of your

monuments, and you will not need to restore them.” This admirer

of the “stones of Venice” was closely followed by Camillo Boito,

who, on behalf of the cathedral at Murano, fought “against the

cleaning, the washing, and the renovation which destroys stains and

colors produced by the great Time.”

By , the call for “conservation instead of restoration”

had grown strong in many European countries. In , Austrian

art historian Alois Riegl published his fundamental thoughts

regarding the values of the past (age, history, and memory) and the

present (use, artistry, and novelty). Behind his “value of age” was

his belief that all works are subject to decay as part of their history.

Their present appearance, he believed, should not deny or hide

their fate.

Riegl’s values are based on a historical and humanistic

approach but also include the practical functions of any interven-

tion. The opposite approach relied mainly on the results of

scientific examination of materials and techniques. A scientific role

in conservation interventions began to increase in the first part of

the th century, though as early as in Paris, artist and dealer

Jean-Baptiste-Pierre le Brun invited chemists to assist in the repair

of a gallery in the national museum. During the th century,

scientific research on the technology of art was firmly established.

The first activity in the Anglo-American countries focused on the

exhibition of cleaned paintings in the National Gallery in

London, which was followed by very fertile discussions of the

“cleaning controversy.”

At present—with the intense cooperation between conserva-

tors, art historians, and scientists—a balanced and complementary

understanding of the problems of cleaning finally seems to have

been reached. This understanding generally relies on common

agreement of the historical uniqueness of every artistic or cultural

relic as an authentic document in all its individual aspects—an

agreement that has been codified in the various charters for the

restoration of art, architecture, and archaeology since .

A Brief History of Cleaning

In antiquity, the application of lye (followed by polishing) was

reportedly used for washing statues. The Romans valued and

retained metallic patinas, mainly on ancient Greek works in bronze.

For facades and interior rooms, since medieval times, periodic

cleaning mostly meant new paints in different colors to give a new

interpretation. Similarly, repainting and alteration were performed

for many polychrome sculptures and mural and easel paintings.

This making clean and looking new with repaintings—and some-

times gilding—for religious sculptures or church furnishings

lasted until the th century. Regarding the general idea that

cleaning should help make things look fresh and new, we should

recall the double meaning of the Italian pulire as cleaning and

polishing, as defined by Baldinucci. Old sourcebooks indicate an

early practical knowledge about cleaning agents and their connec-

tion with revarnishing.

Until the late th century, restoration was usually performed

by artists, often as part of their function as keepers of collections.

Only slowly did restoration become a special profession of art—

a development that emerged first with paintings. The cleaning of a

picture apparently was judged to be a task of art. Even Baroque

painter-restorers, however, were aware of the need to document the

William Hogarth’s 1761 engraving Time Smoking a Picture,the artist’s commentary on the monetary value many in histime placed on items that showed evidence of age anddecay. Photo: Courtesy the Huntington Library.

fact that restoration had been done. For example, in his –

restoration of the wall paintings by Raphael in the Vatican, Carlo

Maratta, head of the Academy in Rome, left an uncleaned area

down in the School of Athens. The restorer in habit of an artist

can be seen in Jan ten Compe’s portrait of Jan van Dijk (the

painting restorer for the City of Amsterdam) cleaning a landscape

painting. Van Dijk, a cotton swab in his left hand, sits in front of his

easel, dishes and bottles for liquids on a small board to the side.

Yellowed varnish has been cleaned from the upper right part of the

landscape painting.

Just four years later, Robert Dossie provided detailed infor-

mation about cleaning practice for painted surfaces in his Hand-

maid to the Arts. He noted that “the art of cleaning pictures and

paintings is of great consequence in preserving valuable works of

that kind, but has been very little understood even by those who

profess to practice it.” Dossie criticized situations in which no

thought was given to the different circumstances and to the effect

of various solvents. He emphasized the need to retain the varnish

when its removal was not necessary or when cleaning an oil painting

would be a risk, while at the same time he advised “the taking off

any foulness . . . by dissolving . . . the matter that constitutes it.”

He systematically listed a range of cleaning mediums from low to

high strength, including water, olive oil, butter, wood or pearl shell

ash, soap, spirit of wine, oil of turpentine, and essence of lemons.

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lFeature 7

The section on the cleaningof pictures and paintings in Robert Dossie’s mid-18th-century book Handmaid tothe Arts. Dossie offeredspecific cleaning techniquesfor painted surfaces. Photo:Courtesy Special Collections,Getty Research Library.

Dossie’s approach was copied by many until the th century,

and such practice continued even after . The old idea of

refreshing surfaces was given new scientific support by chemist

Max von Pettenkofer with the use of solvent vapors for reforming

the surfaces of degraded varnishes—a process that was patented

in Munich in the mid-th century. As a way to avoid the darkening

of varnishes based on oil and/or mastic—and for ease of reversibil-

ity—Friedrich Lucanus introduced dammar resin into restoration

practice in . He also advised restorers to note, on the back

of every picture that they restored, the materials they had used in

their work.

In the field of mural painting, many now-famous pictures

(including The Last Supper by Leonardo da Vinci) had been white-

washed years after their creation. Removing these superimposed

layers became fashionable during the second half of the th

century and was done mainly mechanically by scraping. Works on

stone were treated even more severely. Crusts of deposits—together

with the corroded original surface (including original tool marks

and colorings)—were reduced by chisel and hammer, as was done

by stonemasons for most medieval cathedrals in Europe after about

. In northern and western Europe in the later part of the th

century, cleaning with hydrochloric acid and impregnation with

sodium silicate caused other types of long-term damage to both

painted walls and stone works. By then, sandblasting had come into

use for cleaning works of stone and stucco.

The introduction of new and more efficient techniques for

cleaning was mainly the fruit of closer collaboration between con-

servators and scientists after . This development was sup-

ported by the establishment of interdisciplinary centers for

conservation and research—the Istituto Centrale per il Restauro in

Rome, the Doerner-Institut in Munich, and the Institut Royal du

Patrimoine Artistique in Brussels, among them. With the start of

professional conferences—for example, those organized since

8 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lFeature

by the International Institute for the Conservation of Historic and

Artistic Works, and since by the International Council of

Museums Committee for Conservation—the international debate

on all aspects of cleaning, from theory to practice, intensified and

continues today.

Since the s, totally new perspectives have been intro-

duced into conservation, particularly in the treatment of surfaces

of works of art and monuments. On the diagnostic level, the under-

standing and definition of the characteristics and the condition

of surfaces have deepened, and new instruments, such as microtools

and lasers, have offered ways of mechanical/physical cleaning

previously not possible. On the chemical level, a wide range of

newly tested products—including solvents, soaps, and enzymes—

have come onto the market. But even more important has been the

improvement in controlling solvent action through the use of poul-

tices (with fillers) and pastes or gels for precise control of the area,

penetration, and time.

In the field of stone, plaster, and wall paintings, many surfaces

currently show severe damage from chemical transformation

caused by external deposits or internal transport of acidic or basic

salts. Readily soluble salts can be extracted, but to deal with some

types of damage processes, several methods for chemical passivity

have been developed over the last years for specific cleaning

needs. Similar to the approach of revarnishing painted surfaces

after cleaning is the concept of “sacrificial layers”—a reversible

protective coating and a buffer against weathering. This technique

has proven successful for unpainted plaster and sandstone. The

possibilities for applying new methods have substantially changed

not only the quality but also the delicacy and accountability of con-

servators’ choices of cleaning interventions on the inorganic sur-

faces of monuments and on organic substrates, such as paintings,

paper, and textiles.

Detail of a half-cleaned 17th-century marble sculpture onthe exterior of Salzburg Cathedral. Photo: Manfred Koller.

A partially cleaned portion of an early 18th-century vault painting by Giovanni Antonio Pellegrini in the Salesianerinnenkirche in Vienna. Photo: Manfred Koller.

An Irreversible Intervention

The surface of a work of art must be taken as an archive of its own

history, from its creation to the present. In many cases, the real sta-

tus of a piece, in terms of its origin and history, is little—if at all—

known. This fact makes all the more valuable every artwork still left

uncleaned. Its untouched integrity offers two opportunities—a sen-

sitive one, for the evocation of hidden artistic values, and another

one, for research regarding technology and history of the piece.

These two opportunities are often counter to each other.

Moreover, if all later additions are removed in an attempt to

return a work of art to its “original” status, inevitably the “archive”

of time and history is destroyed. The “original” surface in reality

no longer exists, having suffered several transformations through

time. The idea of recovering any “true” original is therefore an

unrealistic one.

Cleaning has implications both for conservation and for

restoration. As it is an irreversible intervention, every decision and

operation is one of major consequences. The methodology for

undertaking this intervention was clearly put forth by historian

and critic Cesare Brandi, who laid out the criteria for examination

of a work of art: material and technique, history, and aesthetics.

Together they form what Brandi calls “the potential unity of the

work of art,” and they must be considered for cleaning, as well as

for retouching.

Paul Philippot has described the double reality of any object

of art—that it contains both material/technical, and historical/

aesthetic aspects. The task for the conservator is to maintain the

proper balance between these two. “From a critical point of view,”

he writes, “cleaning then becomes the search for an achievable equi-

librium that will be most faithful to the original unity.” When that

equilibrium is achieved, the result could be seen less fatalistically

than art historian Max J. Friedländer perceived the process nearly

a half century ago: “The job of the restorer is a most thankless one.

In the best case, no one is aware of him. . . . His mastery remains

invisible, but his failing becomes evident. . . . Restoration is never-

theless a necessary bad thing.”

Manfred Koller is the head of the restoration department of the AustrianFederal Office for Monuments (Bundesdenkmalamt), a lecturer at theUniversities of Art and Science in Vienna, and coeditor of Restauratoren-blätter, a periodical of the Austrian Group of the International Institute forConservation of Historic and Artistic Works (IIC).

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lFeature 9

Finding a CertainBalanceA Discussion aboutSurface Cleaning

Dial

ogue

The Getty Conservation Institute

is currently conducting a research

project that addresses one of the

critical issues in conservation: the

cleaning of surfaces of art objects.

Cleaning the surface of an object—

which ranges from dirt removal to

replacing a degraded varnish—can

raise a series of questions regarding

aesthetics, the potential loss of

historical information, and the

ability to control the cleaning

process adequately.

The GCI research project attempts

to answer some important questions

regarding the use of solvent-based

gels as cleaning systems. In light

of that work, Institute staff invited

the heads of three Getty Museum

conservation departments to sit

down together to discuss some of the

philosophical and technical issues

related to the surface cleaning

of objects in museum collections.

Participating in the roundtable

discussion were Brian Considine

of Decorative Arts and Sculpture

Conservation, Mark Leonard of

Paintings Conservation, and

Jerry Podany of Antiquities

Conservation. Joining them

in the discussion were Alberto de

Tagle, chief scientist at the GCI,

Narayan Khandekar, a GCI

associate scientist, and Jeffrey

Levin, the editor of Conservation.

10 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lDialogue

Alberto de Tagle: When I first started to work on conservation-

related scientific issues in the early s, one of the main

problems that conservators presented to me was surface cleaning.

Conservators wanted to know what was really happening in the

cleaning process. Since then, I’ve felt that this was a very impor-

tant question that needed to be addressed in general terms.

At this roundtable, I’d like to talk about some of the issues

of surface cleaning from the conservator’s point of view. I’ll start

with an issue at the forefront of discussions of surface cleaning

philosophies, which is that of patina—that much-prized change

of the surface that comes with age. How do you define “patina,”

and how do you keep it when cleaning and removing the undesir-

able changes that occur with time?

Jerry Podany: The complexities of an archaeological artifact’s

surface, or its patina, have been known for some time and certainly

appreciated for aesthetic beauty since antiquity. But the wealth of

information contained in these alteration layers and deposits has

been understood only recently, and it is more appreciated every day.

Because of earlier, certainly more aggressive cleaning techniques,

we’ve lost a great deal of that information for a lot of sculpture

in collections around the world. But our field has changed

considerably in the last several decades. The degree of cleaning has

been reduced dramatically, and cleaning is approached with much

more caution now. What survives on the surface of the object is

highly valued—and that now includes the historic information

offered by artificial patinas applied to ancient sculpture in the th

and th centuries.

Narayan Khandekar: Jerry, the layers that you are trying to

protect are not necessarily man-made or part of the creation

of the object. They have accrued over a period of time.

Jerry Podany: Generally speaking, there are three categories of

patina. One is an alteration layer that occurs due to accidental or

natural change—during burial or weathering, for example. Another

is an intentional coating, perhaps ancient or perhaps applied at a

much later date as part of a restoration or later use. Finally, there

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are those changes or accretions that occur as indirect results of

other intentional actions—rust stains from metal attachments, or

obscuring stains from restoration materials that proved unstable

over time. It can be quite complex and rather subjective to deter-

mine which of these categories have value, alone or in combination

with others.

Narayan Khandekar: The idea of patina in the paintings field begins

with the assumption that something from the underlying paint

layers has penetrated into the varnish, changing the appearance

of the top layer. Does that idea of patina carry across to decora-

tive arts as well?

Brian Considine: Very definitely. The structure of the surfaces we

deal with doesn’t differ significantly from paintings in many cases.

Whether they are oil paint layers or different types of coloring

agents suspended in a binder, it’s really the same type of system.

But there are also some major differences. Terracotta surfaces,

for example, can be very difficult to clean because of their porosity

and because many have an original surface slip that is very lean

in binder.

Jerry Podany: I’d like to ask Mark to comment on controversies in

the cleaning of paintings. Some controversies that have erupted

around sculpture ultimately have been quite healthy for our field—

the recent controversy regarding the overcleaning of some of the

Parthenon sculptures in the British Museum, for example, or the

severe criticism of restorers and conservators by Professor Beck

with respect to the justification of cleaning a number of sculptures.

These criticisms from outside the field have, I think, encouraged us

to look more closely at our own motivations and reasoning. Every-

one—conservator, scholar, art historian, connoisseur, director,

curator—is investigating more carefully why we undertake restora-

tion and if those reasons remain valid. These controversies have

had an enormous effect on sculpture conservation—and I think a

positive one. What about paintings conservation?

Mark Leonard: Everything we do in conservation is geared to be

reversible, but the one thing that is irreversible is cleaning. So it is

the most critical conservation activity. Anything that makes us

question what we are doing and why we are doing it drives our field

to have a deeper understanding of the materials that we are working

with. It is a good thing, even if the process is painful and annoying.

Narayan Khandekar: I have a slightly jaundiced view of cleaning

controversies as related to paintings. I think they’re inevitable.

They have forced conservators to look at their craft, but I’m not

sure how much they’ve directly advanced the cleaning of paint-

ings. I don’t know if they’ve had any other outcome except that

of prompting certain outspoken members of the viewing public—

who appreciate a painting in a certain state—to say that they

don’t like the change.

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lDialogue 11

Brian Considine: I have to disagree. I support Mark and Jerry’s point

of view that any controversy really causes us to question what we

are doing and why we are doing it. I don’t think we can ever do too

much of that. In my department, for example, I sometimes play

devil’s advocate when we are talking about a treatment, because

there is tremendous benefit in really having to articulate your rea-

sons for decisions regarding a treatment.

Mark Leonard: I think we are getting better at dealing with contro-

versies and with the specific issues in a more intelligent fashion. I’m

thinking specifically about the collaborative restoration project we

have with the Yale University Art Gallery on early Italian paintings,

and the work that Narayan has done to identify some original sur-

face coatings that have miraculously survived in a few cases. It has

given us a much stronger foundation upon which to address issues

of our own cleaning and polemics in the past. I hope that kind of

thing will increase. We’re still at the frontier of understanding the

issues of original surfaces in paintings, but I think we are very far

along in valuing those materials. That wasn’t true years ago.

Brian Considine: I have to say that one of the last bastions where

we see an awful lot of damage—and it’s really heartbreaking—is

decorative arts in the marketplace. Furniture, in particular, is auto-

matically stripped, and mounts are regilded. It’s completely aes-

thetically driven; there is some kind of agreement in the market-

place about how a very fine piece of th-century French furniture

should look, and any sacrifice is made to make the object look that

way. It’s common practice for marquetry to be embellished by

adding detail that was not originally there; for Boulle marquetry to

be re-engraved; and for painted objects to be stripped and gilded

instead of painted, because they are worth more in that condition.

Jerry Podany: The desire for a perfect object—and the existence of

restorers who will provide one—has caused damage to antiquities

for centuries. I’ve seen really wonderful objects ruined for the sake

of a brightly polished surface or a pristine form. But the problems

aren’t isolated to the fashions of the market. We have our own

museum fashions affecting conservation and the objects. There are

many large collections of Greek and Roman objects that have had

little maintenance or treatment in many years and that are now,

suddenly, getting a great deal of attention. To be on the “cutting

edge of conservation,” some museums are subjecting their collec-

tions to fairly severe cleaning campaigns, often removing earlier

restorations with little consideration of the value of what is being

removed. As a result, we’re losing a lot of historically important

information about the attitudes of the last years and about the

history of restoration.

Jeffrey Levin: Mark, would you say that the paintings market is

farther along in this regard?

12 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lDialogue

Mark Leonard: I think a little. Fifteen years ago, we rarely saw poten-

tial acquisitions that hadn’t been cleaned, but we were quite vocal

about saying that we wanted to be shown pictures that had not been

touched. The Getty certainly wasn’t the beacon in the field—this

was true for most museums. Now I rarely see a picture that has been

touched. They are usually left alone, and the same is true of pic-

tures sold at Sotheby’s and Christie’s. I think that once it gets into

the broader market, the more expensive the picture, the better

chance it has of finding its way to a good conservator and receiving

proper care. On the less expensive side, things that are kind of

cranked through take on a very different look and a very different

treatment in that process. There is a lot of room for improvement,

but I think we have come a long way.

Alberto de Tagle: One problem is that we don’t have a clear defini-

tion of cleaning.

Narayan Khandekar: In the late s, Gerry Hedley defined three

levels of cleaning for paintings: partial, complete, and selective.

Do you think the field has moved on from that?

Mark Leonard: Yes, we have moved beyond that a bit. In this country

at least, I think there is a general consensus about aesthetic consid-

erations and degrees of cleaning, and certainly a deeper under-

standing about what we are cleaning away, as well as the materials

that we are using to do it.

I worry, however, that the pendulum is swinging just a bit too

far. The more we begin to understand the value of original surfaces,

what can happen—and I’ve seen this in various museums—is that

a kind of paralysis sets in, where you become so terrified of doing

anything that you wind up doing nothing. That may be good in the

short run, and generally no harm comes from doing nothing, but

I hope that as a field we are beginning to find a certain balance

between doing nothing and doing something.

Brian Considine: I’d like to follow up on Mark’s comment about the

pendulum swinging. At the risk of sounding like the enfant terrible,

I think there is a lot of talk about removing an original surface. If

you take furniture as a case in point, sometimes there are very good

reasons to remove an original finish. These are resin coatings that

have a certain life span, and if a table has been subjected to light for

years and the finish is completely crazed and degraded, it is no

longer serving its purpose. You can argue that the finish is actually

obscuring the aesthetic message rather than being part of it.

Jeffrey Levin: So when you remove that surface, you are improving

access to information about the object or to part of its history?

Brian Considine: Yes.

Jeffrey Levin: That’s a choice you make.

Brian Considine: I’m not saying I would always make it, but it is

something to consider.

—Mark Leonard

Alberto de Tagle: Brian, I think you are saying that it depends on

the kind of object, the type of collection, and the message you are

seeking. Would the approach be the same for an archaeological

object from antiquity?

Jerry Podany: It’s different for ancient works. Anything that remains

as part of the original surface is valued as irreplaceable. The prob-

lem is identifying what may be evidence of an ancient decorative or

use-related coating or surface. The effort to do that and the results

have significant implications in our cleaning decisions.

Brian Considine: The point is also that here at the Getty, we are in an

incredibly privileged situation. The majority of people working on

furniture have no access to a microscope.

Jerry Podany: I think you’re getting to a very important complexity

that we should recognize when we talk about what is and is not

cleaned away. For example, let’s consider ancient bronzes—and

only Roman bronzes. Depending on whether that bronze is in an

archaeological museum, an anthropological museum, a study collec-

tion, or a fine arts museum, it may well look entirely different

because the cleaning approach taken was a direct result of the

philosophy and assumptions of that particular type of institution.

If you then compare a Roman bronze and a Chinese bronze in the

same institution, the two objects are often treated completely differ-

ently. Somehow it’s okay to remove what is still termed the “vile”

patina on a Roman bronze, reducing the surface to a smooth and

shiny facade that is completely foreign to the corrosion and cen-

turies it has experienced. But that type of treatment is rarely carried

out on Asian bronzes, because of some romantic idea associated

with the exotic and the assumed philosophical appreciation of nat-

ural processes. While there may be some truth in this, it is mostly a

contradiction and an ill-founded practice. While I agree with Mark

and Brian that it varies object by object, I also think we have yet to

identify these contradictions within types of collections and institu-

tions that directly affect the object.

Brian Considine: Consider how you treat terracotta in the Antiquities

Department and how we treat terracottas. It’s totally different.

Jerry Podany: Yes, you’re right. But in this case there is a great

difference in what we can assume about the original appearance

of the object. We have so little direct information about antiquities,

whereas the closer one gets in time and culture to an object, the

more readily one understands its original intent and form.

Brian Considine: I guess I’m referring to the difference in the aes-

thetic standards for restoration and those for archaeological treat-

ments. We would not repair a loss in a terracotta vase with a plain fill

that was very noticeable.

Mark Leonard: I’d like to return to the issue of “patina,” which is a

word I don’t use in paintings conservation, and one that paintings

conservators as a whole seldom use. There’s an important distinc-

tion. I do talk about the original skin of the picture but patina

implies something more complex, and I think it is more suited to

three-dimensional works of art.

As a paintings conservator, I don’t think I could return an old

picture to what the artist’s original intent was. The materials them-

selves have changed so dramatically over time, and I can never turn

the clock back to make it look the way it did when it left the artist’s

studio. All I can do is work with the changed materials, make some

sense of them, and let them speak in some meaningful way. And

when I find a painting that we think still has its original “skin” or

surface coating, I work within the parameters of that existing sur-

face—but I accept the vast changes that have taken place under-

neath that skin. The pigments have faded in some areas, but not in

others. Some areas have become transparent and dull. Other areas

have retained their original intensity. That complete shift in balance

is what I’m playing with in the cleaning process.

Jeffrey Levin: One of the general impressions I’m getting is that as

conservation has matured, and as it attracts more public atten-

tion, in an ironic way there appears to be at least the beginning

of a shift toward less treatment. Conservation seems to have

become as much an intellectual and philosophical activity—

in terms of evaluating what you’re not going to do, as opposed to

what you may do. Is that correct?

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lDialogue 13

Mark Leonard: It is certainly true in the general sense. But there is

still a lot to be done. I hope we are far more thoughtful about why

we’re doing what we’re doing—and slower in actually doing it. It’s

not unusual for us to have a new acquisition sit in the studio for two

to three months before we do anything, just because it takes that

much time to get to know the object.

Jeffrey Levin: Is it correct to say that years ago some of the

questions you are raising now would not even have been raised?

Jerry Podany: Some of the questions were raised years ago, but

they just hadn’t filtered their way throughout the field. Change in

conservation takes a long time. Whether that change is for the bet-

ter or worse, it’s good to move slowly. We are much more deliberate

today in what we do. We spend a lot more time in introspection,

because of past lessons and because our responsibilities are broader

than they used to be. The more we find out about the potential

impact of what we are doing, the more responsibility it carries with

it. It doesn’t mean that we freeze in our tracks. It just slows us

down, and we act more responsibly.

So in some ways you’re right. But to interpret that as meaning

that our whole job is philosophical—no, as Mark said, there’s

plenty to do. The implications of the ethical and philosophical

issues that have been brought to bear on what we do are that now

nothing is done as a matter of course anymore. Now we look more

carefully at each individual case.

Jeffrey Levin: And the other thing is that in some sense it may take

longer to do less.

Brian Considine: Absolutely. I also feel that one of the most exciting

aspects of conservation now is trying to contribute to the history of

art through technical studies of the objects, the materials, and the

manufacturing processes, the processes of alteration, and the accu-

mulation of subsequent surface coatings or grime.

Jeffrey Levin: How new is this concept of conserving the surface

because it provides information?

Jerry Podany: I think it differs from field to field. You can find very

early examples. The first reference to the beauty of white marble

is in the medieval period. By the th century, they were stripping

everything in sight to reveal that beauty at the expense of seeing

evidence for polychromy. But even then there were those who

warned about the loss. It’s an ongoing debate. The scale keeps

tipping. Right now, conservators are tipping toward caution and

toward avoiding mistakes.

Mark Leonard: One thing that comes up over and over again in

cleaning controversies is scientific objectivity. I think a lot of con-

servation in the past was done in the name of scientific objectivity,

when in fact, what we were really doing was absolving ourselves of

14 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lDialogue

any responsibility. I think, as a field, we understand that now—

perhaps more so than years ago.

Brian Considine: I think there used to be this concept that you could

do something to a work of art and avoid a personal aesthetic judg-

ment. I strongly believe that is not possible. Even the decision to do

something is based on aesthetics in many cases. Even the lightest

cleaning, dusting, or vacuuming involves an aesthetic intervention.

Mark Leonard: Anything you do that changes the look of the work

of art changes the meaning. That can be from the simplest inter-

vention, as Brian described, to a more radical policy.

Brian Considine: It’s a personal aesthetic judgment that you’re

making. It can’t be impersonalized.

Alberto de Tagle: Can we talk about the process by which decisions

are made as to what should or should not be cleaned? Are there

differences in each of your departments in how those determina-

tions are made?

Brian Considine: I would start off by saying that there are at least two

reasons to clean something. Certainly the most pressing one would

be if there was the conviction that a coating was actually detrimen-

tal to the object. That obviously would carry some urgency. The

other reason is the more obvious one—for an aesthetic change. In

that case, we would discuss with the curator the fact that an object’s

current appearance was a very inaccurate representation of the

artist’s intent—that the viewer was being distracted by the dirt or

that it was really falsifying the aesthetic message of the object.

That’s more of an optional intervention. In those cases, the conser-

vators take the lead by researching the material aspects of the

object, learning as much about the artist’s work from the curator,

and gathering information about comparable materials. We would

also possibly research comparable treatments, either within the

department or further afield. We would work with a conservation

scientist to analyze cross sections or carry out different material

analyses of the layers in question, and investigate to see if there is a

cleaning system that would enable us to achieve our aesthetic goals.

It’s really a three-cornered collaboration that involves a lot of

exchange of opinions and information.

Jerry Podany: In the antiquities field, the amount of information

that we now know has been or is still lost through inappropriate

cleaning—ranging from traces of pigment and decorative coatings

all the way to whatever remnant of binder might still be there—

is very sobering to the field. Conservators of artifacts and ethno-

graphic material are intensely aware of the kind of damage and loss

that can occur. At the Getty Museum several decades ago, curators

held enormous sway over what was cleaned and how extensively it

was cleaned. The conservator has always made the decision if

whatever was being removed was dangerous to the object, as Brian

mentioned. But if it wasn’t a direct threat, then it was almost

always an aesthetic decision made by the curator. That has changed

significantly.

We now realize how valuable some of these deposits can be.

Even if we’re trying to target grime that has very little, if any, value,

the action of cleaning may result in the loss of evidence that is there

from antiquity or from some other cultural or historical context.

For example, now there is always a very long waiting period before

we begin to clean. The object may go on exhibition for a long time

before we undertake cleaning. It gives us time to consider the

action and the potential results. I would say that over the last

years, a great number of the objects that were targeted for cleaning

didn’t get cleaned because, over time, discussions brought to light

the fact that there was no benefit in cleaning them, that removing

the encrustation or some disfiguring dirt would not really benefit

the object.

Then we have those cases where cleaning is simply not

possible technically, at least at this moment. We have a number

of objects that we know have brilliant painted designs underneath

the encrustation, but the pigment is more tenaciously attached

to the encrustation than to the terracotta, and so they’re left alone

for now. Your question is a good one, and I think our field is

changing dramatically.

Brian Considine: Part of the reason that it has changed here is

because of our administrative setup, where we have equal access to

the director. In many museums, the conservators report directly

to the curators, so they can have difficulty in not following the

curator’s instructions. In some European countries, the situation

is more difficult because much of the conservation of museum

objects is done by freelance conservators who, in an ethical dis-

agreement, possibly face alienating themselves from future work

at that institution.

Mark Leonard: I think it’s a little different in paintings conservation.

Let me backtrack a bit to answer your question as to how we go

about deciding on whether to clean a painting. At the Getty, we do

operate in an ideal world with regard to our relationship to the

administration and to the curatorial departments, and in our influ-

ence over the care and appearance of the collection. In all respects,

I use as my underlying philosophy, “let the work of art be your

guide.” So the painting is, in fact, the source for determining what

needs to be done to it. That works very well when you have a knowl-

edgeable group of conservators, curators, and conservation scien-

tists who can all talk to one another in a common language and with

a common purpose.

I think the field has matured to the point where conservators

really do play as vital a role as curators in the life of the museum,

and we can play an increasingly public role by being involved in

exhibitions and by helping the public understand what materials

these objects are made from and what has happened to them.

Alberto de Tagle: In the last years, we’ve seen significant

changes in the technical aspects of surface cleaning. Besides

lasers, one of the most controversial cleaning techniques has been

the gel systems—often referred to as the Wolbers methods. Can

you talk about how these methods have contributed to surface

cleaning approaches?

Mark Leonard: I’ll start with what was a kind of epiphany for me,

which is a slide that Richard Wolbers showed during his first lecture

as a Getty Museum Guest Conservator in . It was a cross sec-

tion of a layer of shellac from a piece of furniture that had been

French-polished. The shellac had been applied with repeated rub-

bing as part of the manual application. The cross section showed

that the natural oil in the wood had been drawn up into the French

polish layer.

In that single shot, Richard captured what many paintings

conservators had been talking about for many years—the idea that

the intimacy of the bond between the varnish coating and the oil

paint underneath is much more complex than we have been able to

quantify. Richard took some very important steps toward quantify-

ing the intimacy of those bonds and was able to begin thinking

about putting solvents into gel form to specifically target the kinds

of surface coatings that he was able to identify.

Jeffrey Levin: Mark, that epiphany—that recognition of the

complex relationship of layers of material—is it something

that is now generally shared in the field?

Mark Leonard: I think it’s increasingly understood. I wouldn’t say

that it’s shared as much as it should be. There’s an intuition on the

part of many conservators that cleaning is not simply a matter of

removing a surface coating from a substrate. It would be very sim-

ple to think of removing a varnish from a painting as an on-or-off

proposition. But in fact, the relationship between the varnish and

the paint goes across infinite shades of gray. You never reach a point

where the varnish is all off and only the paint film remains. The

bond that you’re dealing with is so intimate—as was demonstrated

by the slide of that French-polished cross section. The area where

the oil extruded into the varnish and the varnish penetrated into the

wood is this very gray region that I don’t think we completely

understand. Richard Wolbers provided a more scientific foundation

for that intuitive concept that has been refined with the work that

the Getty research team and others elsewhere are doing. But we

have a long way to go.

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lDialogue 15

oTop: Mark Leonard, head of Paintings Conservation at the

The Gels Cleaning Research ProjectBy Valerie Dorge

News

in C

onse

rvat

ion

Getty Museum, using the gelscleaning process in 1988 on the James Ensor painting Christ’s Entry into Brussels(1889). Photo: Elisabeth Mention.

Bottom: GCI associate scientistNarayan Khandekar removing aminute sample from the surfaceof the Ensor painting 12 yearslater. The sample will be analyzedfor possible surface residue.Photo: Dusan Stulik.

O and sometimes controversial stages

of conservation treatment is the surface cleaning of museum

objects—such as paintings, decorative arts, or archaeological mate-

rials—and of monuments.

Painted surfaces especially present difficulties. From an

aesthetic point of view, decisions have to be made regarding partial

or complete removal of varnish or other coatings and/or overpaint

layers. Technical considerations include selection of a method that

allows a great deal of control in the cleaning process, so that unde-

sired layers can be removed without damage to underlying ones.

Artifacts with porous or unpainted surfaces, such as marble or

terracotta, can also present difficulties when grime, stains, or non-

original decorative layers are removed. In addition to aesthetic and

technical considerations, there are ethical ones as well (see “Finding

a Certain Balance: A Discussion about Surface Cleaning,” p. ).

Traditional cleaning methods include mechanical removal

with scalpels or the use of organic solvents or alkali-based aqueous

solutions. With the last two methods, a number of techniques

provide more control—in particular, by slowing the solvent’s

evaporation rate or reducing its migration to surrounding areas.

Conservators of paintings have used wax-solvent pastes, while con-

servators of objects have used thickening agents, including paper

pulp, waxes, clays, and various types of cellulose-based materials.

In the early s, alternative cleaning systems were intro-

duced to the conservation community by Richard Wolbers of the

University of Delaware. The cleaning systems have an aqueous gel

base composed of a polymer resin that thickens with the addition of

water, and a surfactant—also a thickening agent—which improves

the gel’s contact with the surface to be cleaned. Any number of

16 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lNews in Conservation

cleaning agents can be added to this gel base. These include solvents

that dissolve the varnish or undesired paint layer, enzymes that

chemically break down oils, and resin soaps that remove degraded

varnishes (the resin soaps have a chemistry similar to that of the

varnish, and they work on the principle of like-dissolves-like).

The chemical composition of these systems increases the

conservator’s control over the cleaning process. The systems can be

prepared for specific cleaning tasks. Their effectiveness can be

further improved when the conservator has in-depth information

on the chemical composition of the surface to be cleaned; on the

paint-layer stratigraphy; and on the nature of the coating, dirt, or

paint layer to be removed. In addition, they significantly reduce the

conservator’s exposure to volatile toxic organic chemicals. Because

of these important advantages, the new cleaning systems have been

widely incorporated into conservation lab practice.

Nevertheless, a number of concerns have been raised by some

conservators and conservation scientists regarding the possible

long-term effects on surfaces, particularly painted surfaces, of

cleaning with these systems. The most pressing concern has been

whether or not any residue of the gels is left on the treated surfaces—

and, if so, if the residue might pose a danger to the surface. These

dangers would include increasing the solubility of the paint or alter-

ing the paint’s chemistry, thereby possibly accelerating its deterio-

ration. A number of institutions have undertaken studies of various

aspects of possible long-term effects from use of the gels systems.

However, because of the specific focus of these studies, the ques-

tions regarding residue have not been fully answered and remain an

impediment to more widespread use of solvent-based gels.

The Gels Cleaning Research Project

To provide the conservation community with definitive answers on

“the residue question,” the incorporated research on this sub-

ject into a broad scientific research project on surface cleaning,

begun in . The gels project is in collaboration with the

Analytical Laboratory of the Winterthur Museum, Garden, and

Library, the Winterthur–University of Delaware Program in Art

Conservation, and the Department of Chemistry, California State

University, Northridge (). The Getty research team includes

scientists and conservators from the and the Getty Museum.

At the start of the project, three main research areas were

identified: () quantitative measurement of gel component

residues; () aging characteristics of the surfactant components and

investigation of the interaction between gel residue and paint

layers; and () analysis of the surface of paintings cleaned during

the past years with the gels systems. In the course of research,

a fourth subject was added: a study of solvent residue left on and

in paint layers following traditional cleaning with only solvents or

solvent mixtures.

To measure the amount of residue left after use of the gels

systems, the project team developed a highly sensitive methodology

that uses radioactive materials to label the gel components. Four

chemically identical gel formulations were used, each with one

major component labeled. This methodology was applied to a

cleaning experiment carried out in November at . An

international group of conservators and conservation scientists

participated in the experiment (see Conservation, vol. , no. ).

The preliminary results of this study, which is nearly com-

plete, were presented to the conservation community at the biennial

congress of the International Institute for Conservation of Historic

and Artistic Works (), which took place in Melbourne, Australia,

in October . The study showed that there was very little gel

residue left on the cleaned test surfaces. To put this finding into

perspective, the quantities were equivalent to the average amount

of material transferred to a surface by touching it up to times

with a finger. The results of this study will contribute to develop-

ment of parameters for an optimal cleaning procedure.

Current work focuses on identification of decomposition

products of the gel surfactants that have been found to be unstable

under ultraviolet irradiation. This study is performed with the aid

of a residual gas analyzer, which identifies gaseous molecules that

are generated during exposure of the gel residue to ultraviolet light.

Interaction of the residue with the paint film will be studied as well.

Sample films of the four most common types of paint surfaces—

casein, egg tempera, distemper, oil—will be subjected to cycles of

cleaning, varnishing, and aging. The study will attempt to deter-

mine if gel residue is encapsulated during the revarnishing process

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lNews in Conservation 17

and, if so, whether it is removed in a subsequent cleaning. Surface

distribution of the gel residue will be studied through two-dimen-

sional autoradiography—a technique that locates the distribution of

the gel residue in a sample—in combination with laser profilometry,

which measures the topographical features of the cleaned sample

surface. To date, this study has concentrated on the potential

residue on a representative painting—fragments from a large

painting on canvas by Frank Linton that had been vandalized and

subsequently donated to the Winterthur–University of Delaware

Program in Art Conservation.

Because the gels cleaning systems are widely used for cleaning

painted or unpainted objects, the question of gel residue is also

applicable for these materials. Therefore, the existence of residue

and its potential long-term effect for this class of objects is now

being studied. As a first stage, four materials have been identified by

the conservators in the Decorative Arts and the Antiquities depart-

ments of the Getty Museum. These materials—gilded wood,

unglazed terracotta, marble, and plaster—are representative of sur-

faces commonly found on museum objects. They will be subjected

to a cleaning experiment similar to that carried out on the test

painting samples. Modification of the methodology developed for

the initial experiment, especially with regards to sample prepara-

tion, posed a challenge for the project team. The characteristics

of these materials—for example, the hardness of the marble and the

friability of the terracotta—made separation of individual samples

from the prepared panels much more difficult than for the painted

canvas samples. (Separation is needed, as each sample is placed in

a small vial that is then inserted into a scintillation counter that

measures the radioactively labeled components of the residue.)

After a number of ways were tried to separate out the samples, sep-

aration was achieved by scoring (within a millimeter of the surface)

the underside of the sample before cleaning.

Other Studies in the Project

Although the chemical properties of surfactants are known, their

long-term stability under natural and artificial aging conditions has

not been studied. For that reason, two parallel studies are being car-

ried out in the Analytical Laboratory of the Winterthur Museum,

Garden, and Library, to evaluate the deterioration products of a

number of surfactants used in surface cleaning on representative

films, including a linseed oil film.

To date, the films have been analyzed at -hour cycles of

artificial aging—which represent to years of normal museum

lighting conditions—to identify the degradation process. The rate

of change of the nonvolatile surfactants to more volatile degrada-

tion products is currently being examined. Based on the project’s

18 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lNews in Conservation

already completed work measuring the amount of gel component

residues, the artificial aging tests are being repeated, with sampling

at shorter time intervals. Preliminary results indicate that the

surfactants degrade rather quickly. These studies will provide con-

servators with the necessary information to help them select an

appropriate surfactant for a gel formulation.

In a complementary accelerated aging test at the , a quan-

tity of cleaning gel containing the surfactant Ethomeen was applied

to a sample; half of the sample was then covered with aluminum

foil, and the full sample was exposed to ultraviolet radiation. The

amount of radioactivity decreased tenfold during the eight-week

test period of continuous exposure. This indicates that the

Ethomeen is prone to decomposition by ultraviolet radiation and

that some low-molecular products of the decomposition process

evaporate from the irradiated paint surface. This interesting finding

confirms the Winterthur experiments and will help to further the

understanding of what happens to Ethomeen when it is left on the

paint surface after cleaning. Further work on Ethomeen residues

remains to be done.

The third part of the project will involve analysis of the sur-

face of paintings cleaned with gels systems during the past years.

Because these systems were first used in the mid-s on museum

artifacts, analysis of the surfaces of some of these artifacts provides

the potential for determining if any optical or chemical change has

taken place on or within the surface layers over time. It is hoped that

the project’s analyses can identify the source of any such degrada-

tion as a way to determine if the degradation can be linked to

residue from the gel cleaning components.

The two main components of any residue will be the surfac-

tant Ethomeen and the gelling resin Carbopol. Investigation of a

potential analytical method to detect Carbopol in the residue on the

surface of paint samples was successful for a model situation in

which a large amount of sample was available. However, it was not

successful for the small amount of sample that could be taken from

a museum object. Therefore, Ethomeen now is being investigated as

a marker for detecting residue, as the available analytical methods

can identify it more easily. Analysis of samples collected from

objects treated with gels over the last years is just beginning. The

samples were taken from seven th- and th-century paintings

and decorative art objects.

The ongoing studies of gel residue being conducted will

provide an insight into the amount and chemical composition of

residue left on the surfaces of objects following gel cleaning. The

fourth part of the project will compare these residues with possible

residues left by traditional solvent-cleaning methods. A series of

experiments is being performed to provide information on any

solvent residue in the paint layers following solvent cleaning. The

solvents selected are those most frequently used in conservation

practice today in the United States and in Europe: acetone, benzyl

alcohol, dimethylformamide, dodecane, ethanol, isopropanol,

methanol, N-butylamine, toluene, and xylene. This study also

includes an investigation of the potential for even the highest-

purity grades of organic solvents to introduce to the cleaned paint

layer impurities that may not evaporate and which, therefore, may

contribute to any degradation of the paint layer.

An important objective of the gels cleaning research project is

to make the results of its studies available to the conservation com-

munity. In addition, the project seeks to provide conservators with

some recommendations to help them prepare gel formulations that

will be the most effective in the cleaning process or in removing

layers—while minimizing the risk of future damage to surfaces

through degradation from residue or other chemical reactions.

As already noted, the preliminary results from the quantifica-

tion of gel residue were presented at the Congress in Mel-

bourne. Other dissemination efforts are under way. An article

entitled “A Survey of the Conservation Literature Relating to the

Development of Aqueous Gel Cleaning on Painted and Varnished

Surfaces” by project team member Narayan Khandekar will appear

this year in volume of Reviews in Conservation, a peer-reviewed

journal published by the . A full report on the project—includ-

ing the methodology developed for the experiments, the data

obtained, the conclusions reached, and the pertinent recommenda-

tions—will be published by the .

Valerie Dorge is a project specialist with the GCI. Other members of thegels cleaning project assisted in the preparation of this article.

Right: Brian Considine (right), GettyMuseum decorative arts conserva-tor, and David Miller (left), professorof chemistry at California State University, Northridge (CSUN), con-ducting a cleaning experiment on agilded wood sample in the CSUNchemistry laboratory. The objectiveof the experiment is to determine theamount of residue left on the gildedsurface after the gels cleaningprocess. Photo: Valerie Dorge.

Left: GCI project team members Herant Khanjian and Valerie Dorge installing theprepared paint films in the Atlas Weather-Ometer in the GCI scientific laboratories.The films were subjected to 12 weeks ofartificial aging, simulating a museumenvironment. Photo: Dusan Stulik.

Conservation, Th

Members of the Gels CleaningResearch Project Team

Getty Conservation Institute

Valerie Dorge

Nora Ibarra

Narayan Khandekar

Herant Khanjian

Dusan Stulik

Alberto de Tagle

J. Paul Getty Museum

Brian Considine, Decorative ArtsConservation

Joe Godla, Decorative Arts Conservation

Mark Leonard, Paintings Conservation

Jeff Maish, Antiquities Conservation

Eduardo Sanchez, AntiquitiesConservation

Yvonne Szafran, Paintings Conservation

Winterthur Museum

Janice Carlson, Analytical Laboratory

W. Christian Petersen

Winterthur–University of DelawareProgram in Art Conservation

Richard Wolbers

California State University, Northridge

David Miller, Department of Chemistry

Components of Gels Cleaning Systems

The gels cleaning systems have an aqueousgel base that includes a polymer resin and a surfactant. The surfactant is usuallyEthomeen (an ethoxylated [] coco-alkylamine), and the water-based resin isusually Carbopol, a polyacrylic acid.

To this gel base, any number of cleaningsolvents can be added. The most commonsolvents used in the solvent-based gelformulations include acetone, isopropanol,ethanol, toluene, xylene, and benzylalcohol, or mixtures thereof.

e GCI Newsletter lVolume 15, Number 3 2000 lNews in Conservation 19

Preservation inby Aleksey Gibson and Jane Siena Talley

20 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lNews in Conservation

Top: The exterior of the historic Trubetskoy-Naryshkin Mansion, now the permanenthome of the St. Petersburg International Center for Preservation. Photo: Sarah Gore

Bottom: An interior view of the imperial palace of Peterhof, site of the Center’sOctober 2000 seminar on controlling crowds. Photo: Sarah Gore.

AA S. P prepares for its th birthday

in , the St. Petersburg International Center for Preservation

is assuming an increasingly vital role as the only noncommercial

organization devoted exclusively to cultural heritage preservation

in this World Heritage City and former capital of Russia.

The Center for Preservation has grown from a modest part-

nership of three founding organizations—the Russian Academy

of Sciences, the city of St. Petersburg, and the Getty Conservation

Institute—into an independent organization backed by a strong

coalition of over cultural institutions in St. Petersburg and a

range of museums and libraries in the United States and Europe.

The Center’s mission is to encourage and facilitate modern conser-

vation strategies, such as preventive care of collections, through

professional programs in education and training, information

services, collaborative scientific research, and heritage advocacy.

At first temporarily headquartered in the Lavalle Palace, the Center

moved into its permanent home in the historic Trubetskoy-

Naryshkin Mansion on Tchaikovsky Street in June . It is

scheduled to open its new Nicolaas Witsen Information Facility by

the end of .

Since last reported in this publication (see Conservation,

vol. , no. ), the Center has reached a number of significant

milestones in its establishment as a permanent center for the

preservation of the cultural heritage of St. Petersburg and the

surrounding region.

Programs and Resources

Conceived in the aftermath of the disastrous fire at the

Library of the Russian Academy of Sciences, the Center seeks to

implement programs that address the enormous conservation

needs of cultural institutions in St. Petersburg. Ranging from

well-known museums and palace complexes, such as the State

.

St. Petersburg

Hermitage Museum, the State Russian Museum, and the summer

palaces of Tsarskoe Selo and Pavlovsk, to other kinds of institu-

tions, including the National Library, the Academy of Sciences, the

Oriental Institute, and the Mariinsky Theater, these repositories

share similar concerns. Among these concerns are security matters

(ranging from crowd control to theft and terrorism); disaster pre-

paredness; pollution and environmental degradation; fire and

flooding; and collections management and staff training.

To provide Russian curators and conservation professionals

access to the wealth of knowledge available worldwide in the field

of conservation, the Center organizes seminars, symposia, work-

shops, and consultancies. These activities not only serve a didactic

purpose but also create a forum in which conservation professionals

can learn from one another in a collegial environment.

During the – academic year, the Center hosted a

number of seminars and workshops in response to the requests of

its constituents in St. Petersburg. These included an April

seminar entitled “Preventive Conservation: Improved Exhibition

Procedures,” led by experts from the State Russian Museum, the

State Hermitage Museum, and the National Gallery of Art in

Washington, D.C. The seminar addressed exhibition planning from

the viewpoints of aesthetics, conservation, and protection of works

of art. Two months later, conservators from the National Trust in

the United Kingdom, in partnership with staff of Pavlovsk Palace

Museum, led a seminar entitled “Good Housekeeping in Historic

Collections,” sharing their considerable expertise in the cleaning

of historic objects and interiors with colleagues from the various

palace museums and collections in and around St. Petersburg.

As part of its ongoing series on security, the Center also

sponsored, in collaboration with the Russian State Security Bureau

(), “Security Seminar ” in June , led by security experts

from the Getty Trust, the Hermitage, and . This seminar was

devoted to crisis management, disaster preparedness, the prob-

Advisory Council of the St. PetersburgInternational Center for Preservation

Dr. Mikhail Shvydkoy, Minister of Culture, Russian Federation

Dr. Mikhail B. Piotrovski,Director, State Hermitage Museum

Dr. Vladimir A. Gusev, Director,State Russian Museum

Dr. Vadim V. Znamenov,Director, State Peterhof Museum

Dr. Valerii P. Leonov, Director,Library of the Russian Academy of Sciences

Dr. Vladimir N. Zaitsev, Director,Russian National Library

Dr. Alexander D. Margolis,Director, International Foundation for the Salvation of St. Petersburg

Dr. Rudi Ekkart, Director, TheNetherlands Institute for Art History

Dr. M. Kirby Talley Jr., Executive Counselor forInternational Cultural HeritagePolicy, Netherlands Ministry ofEducation, Culture, and ScienceFounding Director, St. PetersburgInternational Center in St.Petersburg

Leaders of RecentSeminars and Workshops

Gordon Anson, Chiefof Production, Design Department,National Gallery of Art, Washington, D.C.

Oleg Boev, Head of Security, State Hermitage Museum

Marilyn Dunn, Conservator,Cornwall Regional Office, National Trust, U.K.

Wilbur Faulk, Senior ProjectManager, Getty ConservationInstitute

Ivan Karlov, Deputy Director andChief Curator, State RussianMuseum

Catherine MacCarthy,Conservator, Severn Regional Office,National Trust, U.K.

Viktor Pavlov, Head of Design,Design Department, State HermitageMuseum

Caroline Rendell, Conservator,Northumbria Regional Office,National Trust, U.K.

Mervin Richard, Deputy Chiefof Conservation, National Gallery of Art, Washington, D.C.

Nikolai Tretiakov, Director,Pavlovsk Palace Museum

Brent Woodworth, Manager,Global IBM Crisis Response Team

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lNews in Conservation 21

lem, and cultural terrorism. Following the seminar, the , in

response to the recent wave of bombings in Russia, approached the

Center with a request to hold a seminar on heritage terrorism. This

seminar focused on the potential threat to cultural institutions.

“Security Seminar ,” in October , was devoted to the prob-

lems of crowd control, particularly at the highly popular summer

palace of Peterhof.

Future programs in planning include seminars and intern-

ships devoted to textile conservation and historic costumes, musical

instrument conservation, and, in collaboration with the Mariinsky

Theater, the restoration of rare th-century musical scores by Ital-

ian composers at the Russian imperial court. Also in the planning

stage is a collaborative project with the Hermitage on saving out-

door sculpture.

A major new resource at the Center will be the Nicolaas

Witsen Information Facility. In the government of the

Netherlands, through the Ministry of Education, Culture, and

Science and the Ministry of Foreign Affairs, decided to establish

the Witsen Information Facility at the Center in honor of the th-

century Dutch scholar and mayor of Amsterdam who fostered early

Dutch-Russian relations. This generous contribution has funded

several new initiatives in information services to assist the Center’s

client institutions. These include: () the first and exclusive office in

Russia of the Art Loss Register; () a specialized preservation

library of foreign and Russian reference sources; () an electronic

communications system linking the Center and its constituent orga-

nizations to other international databases and libraries; and () a

desktop publishing unit.

The Witsen Information Facility is scheduled to open at the

Center before the end of . The Center will also launch its Web

site (www.artsave.ru). The Web site and information facility will

not only allow the work of the Center to be followed around the

world but will also provide its Russian users with the kind of inter-

national access to information and colleagues that can enhance their

own conservation efforts.

Grants, Research, and Advocacy

One of the Center’s objectives is to offer Russian professionals

increased opportunities for professional exchange and study. In that

context, the Center has provided Russian conservators, curators,

and conservation scientists with the opportunity to travel to the

West. During –, under the Center’s auspices, the Royal

Library in The Hague, the Centre des recherches sur la conserva-

tion des documents graphiques in Paris, and the hosted profes-

sionals from St. Petersburg who engaged in research and study.

In the summer and fall of , the Center also gave travel grants to

22 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lNews in Conservation

St. Petersburg professionals, including one to present a paper at an

Oxford University symposium and another to study historic foun-

tain design and maintenance in Spain and Italy.

In tandem with its educational and scientific programs, the

Center sees itself as an advocate for heritage preservation through-

out St. Petersburg. In order to raise awareness of the conservation

needs of the city and its region, the Center seeks to build partner-

ships with Russian government bodies and other like-minded

organizations, such as Save Venice. The Center also promotes

preservation through publications, public lectures, videos, and

exhibitions. For example, the Center assisted the Russian State

Museum in publishing the proceedings of the museum’s April

seminar “The Problems of Storage and Restoration of Art

Museum Collections.” The publication features over papers on

a range of conservation and preventive conservation topics.

Center staff is working closely with Vladimir A. Yakovlev,

governor of St. Petersburg, and other city authorities to ensure

that the celebration attracts international attention to St.

Petersburg’s conservation needs. Support for the Center and its

mission has also come from the national government. Mikhail

Shvydkoy—who was appointed minister of culture of the Russian

Federation this spring—joined the Center’s board of directors in

September and has issued a protocol of understanding from

the Russian Ministry of Culture that strengthens the Center’s

work in the region.

Also joining the Center’s board of directors is Mikhail Pio-

trovski, director of the State Hermitage Museum. In a press release

issued jointly by the Center and the Hermitage in September ,

he announced that the Center “has come through its initial phase

of development by showing that it can organize exactly the types of

collaboration in conservation that are most needed here. . . . Now

we will take a leading role in the St. Petersburg International Center

to support our city’s conservation needs.”

Thanks to the generosity of the St. Petersburg municipal

government, the Center has been able to take possession of the

historic Trubetskoy-Naryshkin Mansion with the understanding

that the Center will restore and maintain this property. In keeping

with its mission, the Center sees the renovation of its own home as

a model for the restoration of other historic properties throughout

the city and is in the process of developing a fund-raising campaign

to meet this goal.

Aleksey Gibson is a research assistant with the GCI. Jane Siena Talley is a GCI senior project specialist and president of the St. PetersburgInternational Center for Preservation.

GC

INew

s

NewProjects

Environmental Guidelines for Collections

Until recently, mechanical engineers did

not possess their own professional techni-

cal resources to guide them in designing

air-conditioning systems for museums,

libraries, and archives when such systems

were specified. Some of the information

that engineers needed concerning environ-

mental specifications was available but

dispersed in many locations within the

conservation literature.

Conservation

Acknowledging this need, the

American Society for Heating, Refrigerat-

ing, and Air-Conditioning Engineers

() began a process in the late s

to add a chapter on air-conditioning sys-

tems in museums, libraries, and archives to

their ASHRAE Handbook. This appeared

as chapter in the edition. Chapters

in handbooks are the efforts of

committees of recognized experts and are

frequently revised. It is not uncommon for

a new chapter to require several revisions at

three-year intervals.

The —in collaboration with the

Canadian Conservation Institute, conser-

vators, and several architects and engineers

in private practice and academia—have

begun the second revision. Changes will

reflect a better balance of gaseous and

particulate filtration with temperature and

relative humidity needs of collections.

There will also be a slightly altered overall

continued on page

Performance of PollutantAdsorbents

Air quality in museums is a major concern

because of the role that pollutants can play

in the deterioration of works of art

indoors—and within indoor microenviron-

ments such as display cases and storage

cabinets. Microclimates with inferior air

quality (due to infiltration of outdoor-

generated pollutants or indoor-generated

pollutants) are often treated by installing an

adsorbent material inside the display case

or storage cabinet.

In the late s, the conducted

research evaluating common adsorbents

used in conservation, including activated

carbon, potassium permanganate, and silica

gel. This research did not point to an opti-

mum adsorbent material. Each material had

drawbacks and advantages. Since that time,

new adsorbents have been developed and

marketed, including zeolites, zinc oxide,

calcium oxides, calcium carbonates, and

continued on page

, The GCI Newsletter lVolume 15, Number 3 2000 lGCI News 23

Environmental Guidelines continued from page

organization to the chapter. This reference

material will apply equally to new con-

struction projects and to historic building

retrofits.

Feedback on the current content

of chapter is eagerly sought from con-

servators and engineers alike. For further

information, please contact either James

Druzik or Cecily Grzywacz at the .

The project is expected to last for at least

the next two years.

Eliska Fucíková, director of theNational Heritage Department inthe Office of the Czech President,and Timothy P. Whalen, director ofthe GCI, listen to Czech PresidentVaclav Havel at the ceremonymarking the completion of conser-vation of The Last Judgment mosaic.Photo: Francesca Piqué.

Pollutant Adsorbents continued from page

adsorbents impregnated with acid neutral-

izing hydroxides. (Research at the Univer-

sity of Glasgow is looking at catalytic

materials to remove hydrogen sulfide.)

The fundamental questions regard-

ing adsorbents—such as which material

should be used for which gaseous pollu-

tants, how much sorbent per enclosure

volume is necessary, and what is the length

of time that each adsorbent is effective—

have not been systemically addressed.

Recognizing the importance of answering

these questions, the has developed a

research project to evaluate the perfor-

mance of pollutant adsorbents.

This new project will test commer-

cially available adsorbents to determine

their capacity for individual pollutants and

their effectiveness in removing the gas

from a microenvironment. Studies will

include monitoring spent adsorbents for

release of the gases (i.e., if the adsorbent

has adsorbed all of the pollutant that it can,

will it gradually release the potentially

damaging gas back into the environment?).

The project, now in the design phase,

will begin testing in early . For further

information, please contact James Druzik

or Cecily Grzywacz at the .

24 Conservation, The GCI Newsletter lVolume 15, Number 3 2

An eight-year international collaboration

among scientists, art historians, and conser-

vators culminated in Prague on September

, , with the unveiling of The Last

Judgment, a th-century glass mosaic that

is one of the Czech Republic’s most signifi-

cant cultural treasures. Czech President

Vaclav Havel joined senior Getty staff at St.

Vitus Cathedral for the first public presen-

tation of the mosaic following completion

of the conservation work that was under-

taken by the and the Office of the Presi-

dent of the Czech Republic.

The Last Judgment, the earliest and

most important monumental exterior

medieval mosaic north of the Alps, covers

square meters ( square feet) of the

cathedral’s south facade. Since its creation

in , the glass mosaic has rarely been

seen in its full splendor. It has faced

repeated threats from wars to fires—and,

more recently, environmental pollutants.

Conservation Completed on St. Vitus Mosaic

Project Updates

000 lGCI News

Divided by Gothic spires into three

sections, The Last Judgment depicts Christ

surrounded by angels in the central panel,

and scenes of heaven and of hell in the two

side panels. The brilliantly colored mosaic

comprises more than a million small glass

tiles and stone pebbles, in more than

different hues. Until now, conservators

have been unable to prevent the recurrence

of a grayish layer of corrosion that

obscures the mosaic.

The current conservation effort

required extensive scientific and art-histor-

ical research and the development of new

conservation methods and materials. In the

process, vital international exchange was

facilitated. The challenge was not merely to

clean the fragile mosaic but to ensure its

future survival by coming up with a coating

that would stabilize and protect it, prevent-

ing further deterioration and allowing it to

remain visible.

The Last Judgment mosaic on St. Vitus Cathedral, following conservation. Photo: Dusan Stulik.

The project team began by analyzing

the mosaic’s material and decay products to

understand the process of deterioration.

Over the course of several years, they then

tested numerous approaches to cleaning

and protecting the mosaic. Actual treat-

ment of the mosaic got under way two and

a half years ago. The central panel was

completed in the summer of , the right

panel in the summer of , and the final,

left panel in the summer of . A team of

and Czech conservators cleaned the

mosaic using special microsandblasters, and

they painstakingly applied a multilayer pro-

tective polymer coating adapted from the

aerospace and medical industries. This is

the first time that the high-tech coating—

developed in collaboration with the

Department of Materials Science Engi-

neering at the University of California, Los

Angeles—has been applied for art conser-

vation purposes.

The project also contributed to major

advances in the art historical analysis of

The Last Judgment mosaic. Archival hold-

ings related to the mosaic have expanded

with the discovery of a number of historical

documents and photographs, as well as

extensive new documentation. The ’s

own holdings of related material now

exceed , items. Conservators who had

worked on earlier restorations of the

mosaic, in the s and s, were also

brought into the process, giving the project

not only a multinational but also a multi-

generational character.

The results of the project team’s

findings will be shared as a service to the

field through publications and a sympo-

sium in June . Additionally, the team

has developed a mosaic maintenance

protocol, to be carried out under the

supervision of Prague Castle to help ensure

the long-term preservation of the conser-

vation work.

In recognition of his substantial con-

tribution to the mosaic’s conservation,

Dusan Stulik, the mosaic’s project manager

for the , was awarded the Presidential

Medal of the Czech Republic. (Stulik, a

senior scientist, is himself a native of

Prague.) In addition, the J. Paul Getty

Trust and the Getty Conservation Institute

were each awarded the Presidential Medal.

Conservati

The and its three project partners—

El Pueblo de Los Angeles, the El Pueblo

Commission, and the El Pueblo Parks

Association—are cooperating to complete

work on the conservation and presentation

of the David Alfaro Siqueiros mural

América Tropical, in El Pueblo de Los

Angeles Historic Monument.

Painted in on the side of the

Italian Hall, the controversial mural, which

depicts a Mexican Indian crucified in a

Mesoamerican landscape, was covered over

with white paint after its creation. Though

América Tropical deteriorated in the

decades that followed, it remains the most

important outdoor mural in Los Angeles.

The project’s goal is to make the painting

accessible to the public and to provide

visitors with an understanding of its his-

toric context.

The project partners are working

together on several fronts. First is the

design of a shelter and a viewing platform

for the mural. The architectural firm of

Pugh+Scarpa is designing a shelter for the

mural that will meet three criteria—to pro-

tect the mural as much as possible from the

elements, to blend in with the surrounding

historic district, and to allow the entire

mural to be seen from a viewing platform.

The final conservation and cleaning

of the mural will occur once the new shel-

ter is in place. América Tropical is stable in

its present condition, and it will be padded

and boxed during the rooftop construction

América Tropical

on, The GCI Newsletter lVolume 15, Number 3 2000 lGCI News 25

phase of the project. Following construc-

tion, the conservation and cleaning will

take approximately three months.

Another part of the project is an

interpretative center for the mural. América

Tropical is an important monument of both

Los Angeles history and the Mexican

mural movement. The design firm of

Magic has begun work on the didactic

materials and on the design of the interpre-

tive center, to be housed in the historic

Sepulveda House. Access to the rooftop

viewing platform will be through the inter-

pretive center.

Completion of the project will

require fund-raising. In addition to the

funding that the , the City of Los

Angeles, the Friends of Heritage

Preservation, and other foundations have

committed to the project, an additional

million is needed to complete work.

A fund-raising campaign began in late

to raise this sum.

The current timetable to which the

project partners are committed calls for

work to be completed by the spring of

, in time for this significant monument

of history and art to be made accessible to

the public years after its creation.

A detail of the Siqueiros mural América Tropical. Photo: Nancy Kaye.

26 Conservation, The GCI Newsletter lVolume 15, Number 3 20

As a part of the ’s Maya Initiative—

which focuses on advancing regional con-

servation practice and collaboration among

the countries of the area—the is

involved in a partnership with the Instituto

Hondureño de Antropología e Historia

() to develop a conservation plan for

the hieroglyphic stairway at the Maya site

of Copán in Honduras. The stairway,

meters wide by meters high ( feet by

feet), is composed of steps with over

, intricately carved Maya glyphs. It

was rediscovered a century ago after being

buried for over a thousand years.

The commissioned a measured

survey to gather the precise data required

to provide a condition evaluation, create

a basis for site monitoring, and guide an

intervention strategy. Digital photogram-

metry was the survey method selected

because of its capability of providing a

precise map of the surface features. The

site survey, which was conducted in June

, consists of two elements: overlap-

ping stereo photography, done with a

specialized survey (metric) camera, and

survey observations recorded with a total

station. Photarc Surveys of the United

Kingdom was selected to carry out the

photography, and the staff gathered the

survey measurements.

Measures were taken to protect both

the stairway and the survey team and to

ensure that contact with the stairway’s

stone surfaces was kept to an absolute min-

Documentation ofHieroglyph Stairway in Copán

00 lGCI News

imum. Because the site is protected by a

large tarpaulin suspended only a few feet

from the surface, hundreds of camera

setups were required to obtain the ,

photographs and over , control obser-

vations necessary to complete the project.

The photography is already being used as a

basis for the condition assessment. The data

collected provide a unique record of the

stairway and have the potential—by means

of a digital photogrammetry workstation—

to produce a three-dimensional model of

the stairway to millimeter precision.

A detail of the hieroglyphic stairway at Copán. Photo: William S. Ginell.

A three-day meeting on photographic

preservation was held in early August at

the Image Permanence Institute () in

Rochester, New York, cosponsored by the

and the . The purpose of the meeting

was to identify and prioritize important

conservation and research issues with

regard to the preservation of photographic

collections. In addition, those attending

discussed the feasibility and impact of

various photographic conservation

research activities and attempted to iden-

tify potential collaborations and directions

for future research.

Recent Events

Meeting on PhotographicPreservation

Thirty conservators, curators, and

conservation scientists participated in the

discussions in Rochester. Included were

conservation scientists from the , the

, and the Research Center for the Con-

servation of Graphic Documents in Paris.

Also attending were curators from

Eastman House; conservators and educa-

tors from Delaware, New York, and

Denmark, and from the J. Paul Getty

Museum; Mellon advanced fellows in pho-

tographic conservation; and conservators

in private practice.

The meeting was a unique opportu-

nity for a broad and open discussion of the

current state of research in photographic

collections. Conservators, curators, and

conservation scientists had the chance to

exchange ideas on research approaches,

priorities, and partnerships. Little has been

done until now related to the characteriza-

tion of photo materials, their deterioration,

and their reaction to treatments; it is hoped

that this meeting, and subsequent discus-

sions, will result in valuable new research

that will advance the state of photographic

conservation.

Conservatio

A Tribute to AlessandraMelucco Vaccaro

Tributes

Conservator, teacher, and writer Alessan-

dra Melucco Vaccaro passed away in Rome

in September after a long illness.

Alessandra was an esteemed and val-

ued colleague of the staff of the , who

contributed in various ways to the work of

the Institute. As one of the editors of the

’s publication Historical and Philo-

sophical Issues in the Conservation of Cul-

tural Heritage, her very valuable knowledge

of modern conservation theory and archae-

ological conservation helped to shape the

form and substance of the book. She was

an engaged and thoughtful participant in

the Conference on Conservation of

Archaeological Sites in the Mediterranean

Region, organized by the and the Getty

Museum. She also participated in the ini-

tial California meeting that launched

the Institute’s research on the values of

heritage conservation.

Born in , Alessandra studied

classical archaeology at the University of

Rome, under the direction of Ranuccio

Bianchi Bandinelli. After her graduation,

she joined the Ministry of Cultural Her-

itage and worked at the Soprintendenza

alle Antichità in Florence and in Ostia

Antica. From there, she moved on to a

position as curator at the Museo dell’Alto

Medioevo in Rome.

As the director of the Department of

Archaeological Conservation at the Istituto

Centrale per il Restauro in Rome from

to , she oversaw numerous con-

n, The GCI Newsletter lVolume 15, Number 3 2000 lGCI News 27

servation projects, including the work done

on the Riace bronzes, the equestrian monu-

ment of Marcus Aurelius of the Capi-

tolium, the Arch of Constantine, and

Trajan’s Column.

She went on to teach architectural

and archaeological conservation at the

University of Venice and at the Istituto

Suor Orsola Benincasa in Naples. During

her last five years, she directed a section of

the Central Office of Cultural and Envi-

ronmental Heritage of the Ministry of

Cultural and Environmental Affairs that

dealt with the protection of cultural land-

scapes and with relationships among inter-

national organizations. Through this work,

she was very active in organizations such as

, the World Heritage Center, and

the Council of Europe.

Greatly concerned with the conser-

vation of archaeological sites, she was one

of the promoters and directors of the Carta

del Rischio project (the risk map of cul-

tural heritage) and the EuroMed project,

Programmation Integrée des Sites

Archéologiques (). During her career,

she authored a large number of articles and

monographs on issues of archaeological

conservation and the protection and man-

agement of cultural landscapes. For these

and her many other contributions to the

field, Alessandra will long be remembered.

28 Conservation, The GCI Newsletter lVolume 15, Number 3

A Tribute to Leonetto Tintori

Leonetto Tintori, sculptor, painter, and

internationally eminent wall paintings

conservator, died in July at his home

in Vainella, near Prato, Italy. He was

years old.

Leonetto was part of a generation of

men and women whose lives and careers

are inextricably linked to the development

of what is now called conservation science.

The son of a farmer, he entered the

restoration field as an imbianchino, or wall

repairer and painter. He had trained as an

artist in his hometown of Prato, but his

knowledge of restoration and conservation

was earned on the job. Under the guidance

of a well-known Florentine painter,

Ardengo Soffici, whose house he was deco-

rating, Leonetto started working as a con-

servator, repairing some th-century wall

paintings discovered under the whitewash.

He went on to work on the most

important cycles of wall paintings in Italy.

By the mid-s, Leonetto was part of

Ugo Procacci’s restoration group in Flo-

rence, working on wall paintings by Giotto,

Simone Martini, Masaccio, Piero della

Francesca, and many others. At the end of

World War , he achieved renown for his

part in saving the wall paintings in the

Cimitero Monumentale in Pisa. By the

s he had his own conservation team,

which for years studied original tech-

niques and materials, collaborated with sci-

entists, and introduced new materials for

2000 lGCI News

treating paintings. In the aftermath of the

flood in Florence, the group success-

fully introduced new measures for the

emergency stabilization and consolidation

of wall paintings and paintings on wood.

In each conservation project,

Leonetto saw the need to understand the

original painting technique—not only to

further his knowledge and appreciation of

the artistic achievement but as a require-

ment for the proper identification of the

conservation methods and materials com-

patible with those used by the artist. When

he could not find adequate answers for

complex conservation problems, he sought

expertise from other professions, and he

was one of the first conservators to collabo-

rate with scientists. He was also a pioneer

in insisting upon documentation, establish-

ing a tradition of detailed reports with sys-

tematic use of photographs. Leonetto was

among the first in the field to publish

reports on his work, collaborating on these

articles with other professionals. Conserva-

tors, scientists, and art historians from

abroad came to study and exchange ideas

with him.

The quality of his conservation work

is only a part of his legacy, for Leonetto

was also a natural teacher, a great colleague,

a tireless student, and a genuine innovator.

In his later years, Leonetto and his wife

Elena turned their house into an interna-

tional school and laboratory for the study

of the ancient art of painting a fresco.

A visit to the house was a journey to a place

wholly devoted to art, art making, and an

understanding of traditional techniques

and materials. A stroll in the garden

brought encounters with sculptures large

and small that waited like old friends along

the path. The walls of the house and stu-

dios were used as panels where students

practiced all aspects and variations of

wall painting techniques, from mixing

and laying on the lime plaster to applying

the paint made with mineral pigments

dispersed in water.

In this small corner of paradise,

Leonetto—after a busy career as a wall

paintings conservator—continued to study,

experiment, write, and make his own art

until his death.

Leonetto Tintori’s main desire was to

truly understand how great artists created

their works. He believed that it was only

through scientific analysis and testing that

this could be achieved. His efforts have

influenced countless conservators and

artists. His experience and intellect—and

his passion for learning and experiment-

ing—will be sorely missed.

Leonetto Tintori. Photo: Francesca Piqué.

Publications

Cave Temples of Mogao Art and History on the Silk Road

By Roderick Whitfield, Susan Whitfield, and Neville Agnew

The Mogao grottoes in China, situated

near the oasis town of Dunhuang on the

fabled Silk Road, constitute one of the

world’s most significant sites of Buddhist

art. In some five hundred caves carved into

rock cliffs at the edge of the Gobi Desert

are preserved , years of exquisite

murals and sculpture. Mogao, founded by

Buddhist monks as an isolated monastery

in the late fourth century, evolved into an

artistic and spiritual mecca whose renown

extended from the Chinese capital to the

far western kingdoms of the Silk Road.

Among its treasures are miles of stunning

wall paintings, more than , statues,

magnificent works on silk and paper, and

thousands of ancient manuscripts, such as

sutras, poems, and prayer sheets, which in

Conservation

were found sealed in one of the caves

and then dispersed throughout the world.

Illustrated in color throughout, Cave

Temples of Mogao combines lavish pho-

tographs of the caves and their art with the

fascinating history of Mogao, Dunhuang,

and the Silk Road to create a vivid portrait

of this remarkable site. Chapters discuss

the development of the cave temples, the

iconography of the wall paintings, and the

extraordinary story of the rare manu-

scripts—including the oldest dated printed

book in existence, a th-century copy of

the Diamond Sutra. Also discussed are the

collaboration between the Getty Conserva-

tion Institute and Chinese authorities in

conservation projects at Mogao and the

ways in which the site can be visited today.

The publication of this book coincides

with the centenary of the discovery of the

manuscripts in the Library Cave.

Roderick Whitfield is Percival David

Professor of Chinese and East Asian Art,

School of Oriental and African Studies,

University of London, and corresponding

fellow of the Dunhuang Academy. Susan

Whitfield is head of the International Dun-

huang Project, British Library. Neville

Agnew, who has worked on conservation

projects at Mogao for years, is principal

project specialist at the Getty Conservation

Institute, a research fellow of the Dun-

huang Academy, and the editor of Conser-

vation of Ancient Sites on the Silk Road..

Conservation and Cultural Heritage series144 pages, 8 x 10 inches144 color and 12 b/w illustrations, 1 mapISBN 0-89236-585-4, paper, $29.95

, The GCI Newsletter lVolume 15, Number 3 2000 lGCI News 29

30 Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lGCI News

Staff Profiles

Valerie GreathouseReference Librarian, Information & Communications

Den

nis

Kee

ley

Kevin EllisSenior Technical Support Specialist,Administration

Den

nis

Kee

ley

This book describes tests performed on

model adobe buildings to evaluate seismic

damage mitigation techniques applicable to

the retrofitting of historic and culturally

significant adobe structures. Part of the

’s Getty Seismic Adobe Project (),

the three-year program outlined in this

volume was designed to develop and test

minimally invasive, inexpensive, and easily

implemented methods of protecting such

structures from severe earthquake damage.

Small- and large-scale models were tested

on computer-controlled shaking tables at

Stanford University and at the Earth-

quake Engineering Laboratory in the

Republic of Macedonia, respectively. The

authors identify typical failure modes of

adobe structures and describe specific

retrofit techniques to help minimize such

failures. Extensive photographic documen-

tation is included.

E. Leroy Tolles is a structural engi-

neer with & Associates and was princi-

pal investigator for . Edna E. Kimbro

is an architectural conservator and histo-

rian specializing in the preservation of His-

panic-era buildings and material culture.

Frederick A. Webster is a civil engineer

who specializes in design, repair, and

retrofitting of historic buildings. William

S. Ginell is a senior conservation research

Seismic Stabilization ofHistoric Adobe Structures Final Report of the Getty Seismic Adobe Project

By E. Leroy Tolles, Edna E. Kimbro, Frederick A. Webster, and William S. Ginell

scientist at the Getty Conservation

Institute and was project director of .

Tolles, Webster, and Kimbro are coauthors,

with Anthony Crosby, of Survey of

Damage to Historic Adobe Buildings after the

January Northridge Earthquake.

GCI Scientific Program Reports series158 pages, 81⁄2 x 11 inches286 b/w illustrations, 15 drawingsISBN 0-89236-587-0, paper, $40.00

Valerie Greathouse is on the

staff of the ’s Information

Center, where she primarily

does reference and research

work, recommending informa-

tion strategies in conservation

to Getty staff and conservators

worldwide. She also serves as

liaison to the Getty Research

Library and represents the

on committees for the Library’s

online catalogue.

Valerie grew up in

Los Angeles. Her father was a

sound effects artist and engi-

neer at Radio. Her

mother—who worked in

aerospace and raised money

for medical research—had

intended to be a librarian, and

Valerie became a bibliophile at

an early age, one with a passion

for archaeology that developed

after reading a children’s

magazine article about

Tutankhamun and the daugh-

ter of Akhenaten.

After earning a B.A. in

psychology from (with a

minor in anthropology and

archaeology), she took a

research position in mental

health evaluation at and

entered the School of Public

Health’s master’s program.

Her master’s research in behav-

ioral sciences and education

involved the retrieval, analysis,

and dissemination of evalua-

tion information. During this

period, she managed a large

research grant at and

supervised an abstracting and

indexing unit. In the following

years, she worked for several

information services compa-

nies, and her career as an infor-

mation professional included

research and training in infor-

mation retrieval, consulting in

information management sys-

tems and database design, and

marketing of information sys-

tems and services.

In she got a call

from a former colleague who

was doing temporary work for

the ’s Art and Archaeology

Technical Abstracts (AATA).

The friend told her, “This is

your kind of place—indexing

and abstracting, online data-

bases, and Nefertari.” After

two months in a temporary

position, Valerie became assis-

tant editor of AATA, where she

remained for five years. She

also worked on the Conserva-

tion Thesaurus and the

AATA/Bibliographic Conser-

vation Information Network

database. She then joined the

staff of the Information Center.

Her outside interests

include not only history and

archaeology but also the per-

forming arts, photography,

cruising the California Channel

Islands in her family’s sailboat

(visiting the Chumash rock art

site on Santa Cruz Island), and

beachcombing and kayaking in

Mexico’s Sea of Cortez. In

addition to her position at the

, Valerie has, as she puts it,

worked as a mom for years

and been married forever.

As part of the ’s administra-

tive group, Kevin Ellis manages

the Institute’s computer

hardware and helps coordinate

implementation of Getty

Trust data acquisition systems.

He also works closely with the

Institute’s liaison to Informa-

tion Technology Services at

the Getty.

Born in Los Angeles,

Kevin was raised in the suburb

of Glendale. His parents were

also native Angelenos. His

father was a computer consul-

tant, and Kevin, at the age of

, regularly accompanied him

at night to large computer facil-

ities where he had rented time

for information processing.

These were Kevin’s first mem-

ories of computers.

After high school—

where he excelled in water

polo—Kevin did construction

work for a couple of years

before being hired by City

National Bank as an entry-level

data processor. At the same

time, he started taking courses

in computer science and busi-

ness administration at Glendale

College. After a year with the

bank, he got a job with the Jet

Propulsion Laboratory in

Pasadena, where he worked ini-

tially doing computer service

and repair, then later helped

install and maintain ’s first

local area network. Although he

enjoyed the exciting and ener-

getic environment at , he left

after five years to join a start-up

software company where he

could pursue his interest in

becoming a systems program-

mer. While there, he worked on

the development of informa-

tion systems for hospitals.

In he was hired by

the to provide on-site com-

puter support at the Institute’s

original headquarters in the

Marina del Rey section of Los

Angeles. He went on to imple-

ment the Institute’s first inter-

nal network and project

administration system. Since

the ’s move to the Getty

Center in , his daily role

has changed—he now has more

administrative and budgetary

responsibilities.

Kevin—who began boat-

ing with his family at the age of

two—can be found on week-

ends sailing the waters off Long

Beach. A competitive yacht

racer since , he is a board

member of the Alamitos Bay

Yacht Club, as well as one

of the club’s principal race

officers. Perhaps his most

memorable yachting experi-

ence was as part of a five-man

crew on a -day, ,-mile

trip aboard a racing sloop that

sailed from Honolulu to Long

Beach in the summer of .

Conservation, The GCI Newsletter lVolume 15, Number 3 2000 lGCI News 31

Feature 5 Surface Cleaning and Conservation

Dialogue 10 Finding a Certain Balance

A Discussion about Surface Cleaning

News in 16 The Gels Cleaning ResearchConservation Project

20 Preservation in St. Petersburg

GCI News 23 Projects, Events, Publications, and Staff